1. Field of the Invention
The present invention relates to parts for two-wheeled vehicles and, more particularly, to a sensor unit for storing therein a sensor for detecting revolving speed of wheels of bicycles or the like.
2. Description of the Background Art
Recently, speedometers are sometimes attached to bicycles in order to readily know travel speed, travel distance and the like of the bicycles.
FIG. 5 is a side view of a conventional bicycle to which a speedometer is attached; and FIG. 6 is an enlarged view of a portion denoted with a symbol "X" of FIG. 5.
Referring to FIGS. 5 and 6, a speedometer 30 is mounted on a stem 31 of a handle of a bicycle 24. A magnet 26 is attached to a spoke 32 of a front wheel of the bicycle. A sensor 28 for generating one pulse signal each time magnet 26 passes in front of sensor 28 is mounted on a portion of a fork 34 corresponding to magnet 26.
The signal generated by sensor 28 is input through a cord 11 to speedometer 30. Then, various types of operations are carried out in response to the input signal in speedometer 30. Information as to the calculated speed, travel distance and the like is supplied to a user.
FIG. 7 is an enlarged view of sensor 28 of FIG. 6; FIG. 8 is a side view of sensor 28 taken along the line VIII--VIII of FIG. 7; and FIG. 9 is a section view of sensor 28 taken along the line IX--IX of FIG. 7.
A description will now be made on the structure of a conventional sensor unit with reference to those figures.
Sensor unit 28 comprises a sensor storage 39 for storing therein a reed switch 29 constituting the sensor, a sensor cover 35 for covering sensor storage 39, a band 5 for fixing sensor 28 onto fork 34, and a screw 7 for mounting sensor cover 35 pivotally on band 5.
In sensor cover 39, reed switch 29 is soldered onto a base plate 25, and core wires of a cord 27 externally connected in sensor cover 39 are each soldered onto base plate 25. Sensor storage 35 and sensor cover 39 are combined together in concave and convex forms as shown in the figure. In order to protect reed switch 29 or the like against rainwater or the like introduced from the outside, reed switch 29, base plate 25, cord 27, the core wires thereof and the like are resin-sealed by polyurethane 41. In such a manner, the inside of the sensor is protected against water drops or the like introduced between sensor storage 35 and sensor cover 39.
In the above-described conventional sensor unit, since it is necessary to seal the sensor with such resin as polyurethane or the like, it takes time to manufacture the sensor unit. Further, once the sensor is sealed with resin, any defects of reed switch 29, base plate 25 and the like cannot easily be inspected or repaired, resulting in a decrease in yield.